Recent Trends in Lateral Flow Immunoassays with Optical Nanoparticles.

Rapid, accurate, and convenient diagnosis is essential for effective disease management. Various detection methods, such as enzyme-linked immunosorbent assay, have been extensively used, with lateral flow immunoassay (LFIA) recently emerging as a major diagnostic tool. Nanoparticles (NPs) with characteristic optical properties are used as probes for LFIA, and researchers have presented various types of optical NPs with modified optical properties. Herein, we review the literature on LFIA with optical NPs for the detection of specific targets in the context of diagnostics.

Characteristics of febrile seizures with SARS-CoV-2 infection in the Omicron era.

Background: While the pandemic of coronavirus disease 2019 (COVID-19) is ongoing, the Omicron variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been dominant recently. The Omicron variant causes more seizures in pediatric patients compared with previously circulated variants. This study aimed to investigate the incidence and clinical features of febrile seizure (FS) in pediatric patients with COVID-19 during the Omicron era. Methods: The medical records of pediatric patients (≤18 years of age) diagnosed with COVID-19, who presented with FS between February 2020 and June 2022, were reviewed retrospectively to analyze clinical characteristics of FS in seven university-affiliated hospitals of Korea. Results: Of 664 pediatric patients with COVID-19 during the study period, 46 during the pre-Omicron period and 589 during the Omicron period were included in the study analysis; 29 patients during the transition period were excluded. Among the included patients, 81 (12.8%) had concomitant FS, and most (76.5%) experienced simple FS. All FS episodes occurred during the Omicron period and none of them during pre-Omicron period (P=0.016). Sixty-five (80.2%) and 16 (19.8%) patients were categorized as FS (patient age ≤60 months) and late-onset FS (patient age >60 months), respectively. Underlying neurologic disease (P=0.013) and focal onset seizure (P=0.012) were more common in the late-onset FS group than in the FS group; however, overall clinical manifestations and outcomes including seizures consistent with characteristics of complex FS and subsequent epilepsy were similar between the two groups. Conclusions: As the COVID-19 pandemic persists, the incidence of FS has increased with the emergence of the Omicron variant. About one-fifth of the patients experiencing FS due to infection by the Omicron variant of SARS-CoV-2 were aged >60 months; however, clinical characteristics and outcomes were favorable. More information and long-term prognoses in patients with FS due to COVID-19 should be acquired.

Mouse models of lung-specific SARS-CoV-2 infection with moderate pathological traits.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causing coronavirus disease 2019 (COVID-19) has been a global health concern since 2019. The viral spike protein infects the host by binding to angiotensin-converting enzyme 2 (ACE2) expressed on the cell surface, which is then processed by type II transmembrane serine protease. However, ACE2 does not react to SARS-CoV-2 in inbred wild-type mice, which poses a challenge for preclinical research with animal models, necessitating a human ACE2 (hACE2)-expressing transgenic mouse model. Cytokeratin 18 (K18) promoter-derived hACE2 transgenic mice [B6.Cg-Tg(K18-ACE2)2Prlmn/J] are widely used for research on SARS-CoV-1, MERS-CoV, and SARS-CoV-2. However, SARS-CoV-2 infection is lethal at ≥105 PFU and SARS-CoV-2 target cells are limited to type-1 alveolar pneumocytes in K18-hACE2 mice, making this model incompatible with infections in the human lung. Hence, we developed lung-specific SARS-CoV-2 infection mouse models with surfactant protein B (SFTPB) and secretoglobin family 1a member 1 (Scgb1a1) promoters. After inoculation of 105 PFU of SARS-CoV-2 to the K18-hACE2, SFTPB-hACE2, and SCGB1A1-hACE2 models, the peak viral titer was detected at 2 days post-infection and then gradually decreased. In K18-hACE2 mice, the body temperature decreased by approximately 10°C, body weight decreased by over 20%, and the survival rate was reduced. However, SFTPB-hACE2 and SCGB1A1-hACE2 mice showed minimal clinical signs after infection. The virus targeted type I pneumocytes in K18-hACE2 mice; type II pneumocytes in SFTPB-hACE2 mice; and club, goblet, and ciliated cells in SCGB1A1-hACE2 mice. A time-dependent increase in severe lung lesions was detected in K18-hACE2 mice, whereas mild lesions developed in SFTPB-hACE2 and SCGB1A1-hACE2 mice. Spleen, small intestine, and brain lesions developed in K18-hACE2 mice but not in SFTPB-hACE2 and SCGB1A1-hACE2 mice. These newly developed SFTPB-hACE2 and SCGB1A1-hACE2 mice should prove useful to expand research on hACE2-mediated respiratory viruses.

COVID-19 vaccine type-dependent differences in immunogenicity and inflammatory response: BNT162b2 and ChAdOx1 nCoV-19.

Evaluation of the safety and immunogenicity of new vaccine platforms is needed to increase public acceptance of coronavirus disease 2019 (COVID-19) vaccines. Here, we evaluated the association between reactogenicity and immunogenicity in healthy adults following vaccination by analyzing blood samples before and after sequential two-dose vaccinations of BNT162b2 and ChAdOx1 nCoV-19. Outcomes included anti-S IgG antibody and neutralizing antibody responses, adverse events, and proinflammatory cytokine responses. A total of 59 and 57 participants vaccinated with BNT162b2 and ChAdOx1 nCoV-19, respectively, were enrolled. Systemic adverse events were more common after the first ChAdOx1 nCoV-19 dose than after the second. An opposite trend was observed in BNT162b2 recipients. Although the first ChAdOx1 nCoV-19 dose significantly elevated the median proinflammatory cytokine levels, the second dose did not, and neither did either dose of BNT162b2. Grades of systemic adverse events in ChAdOx1 nCoV-19 recipients were significantly associated with IL-6 and IL-1ß levels. Anti-S IgG and neutralizing antibody titers resulting from the second BNT162b2 dose were significantly associated with fever. In conclusion, systemic adverse events resulting from the first ChAdOx1 nCoV-19 dose may be associated with proinflammatory cytokine responses rather than humoral immune responses. Febrile reactions after second BNT162b2 dose were positively correlated with vaccine-induced immune responses rather than with inflammatory responses.

Different antibody responses between liver and kidney transplant recipients elicited by third doses of COVID-19 mRNA vaccines.

Background: Solid organ transplant recipients exhibit decreased antibody responses, mainly due to their weakened immune systems. However, data are limited on antibody responses after the primary series of coronavirus disease 2019 (COVID-19) vaccines among recipients of various solid organ transplant types. Thus, we compared the antibody responses after three COVID-19 vaccine doses between liver transplant (LT) and kidney transplant (KT) recipients. Methods: We prospectively enrolled solid organ transplant recipients who received three COVID-19 vaccine doses from June 2021 to February 2022 and measured S1-specific immunoglobulin G antibodies using an enzyme-linked immunosorbent assay. Results: Seventy-six LT and 17 KT recipients were included in the final analysis. KT recipients showed consistently lower antibody responses even after the third vaccine dose (86.2% vs. 52.9%, P=0.008) and lower antibody titers (median, 423.0 IU/mL [interquartile range, 99.6-2,057 IU/mL] vs. 19.7 IU/mL [interquartile range, 6.9-339.4 IU/mL]; P=0.006) than were observed in LT recipients. Mycophenolic acid was a significant risk factor for a seropositive antibody response after the third vaccine dose in the multivariable analysis (odds ratio, 0.06; 95% confidence interval, 0.00-0.39; P=0.02). Conclusions: We found a weaker antibody response despite the completion of the primary series of COVID-19 vaccines in KT recipients than in LT recipients. Mycophenolic acid use in KT recipients might be the main contributor to this observation.

Afebrile benign convulsions with or without a reversible splenial lesion in two pediatric patients with COVID-19.

BACKGROUND: Seizures in children with coronavirus disease 2019 (COVID-19) were markedly increased during the Omicron variant surge. Most seizures occurred with fever. New-onset afebrile seizures were rarely reported; therefore, their courses are not well-known. CASE PRESENTATION: Two patients (7 and 26 months of age, respectively) with COVID-19 showed recurrent afebrile seizures immediately after resolution of a fever lasting for 2-3 days. Bilateral convulsive seizures lasted for approximately 1 min/episode (6 of 7 total episodes) and occurred 3-4 times within 2-3 h. However, the patients were alert between seizures, which is in contrast to seizures occurring with encephalopathy or encephalitis. Only one episode required acute antiseizure medication. Brain magnetic resonance imaging showed a reversible splenial lesion in one patient. The serum uric acid level was slightly increased (7.8 mg/dL) in this patient. Electroencephalography findings were all normal. During the follow-up period, no seizures or developmental problems have been observed. CONCLUSIONS: COVID-19-associated, afebrile benign convulsions with or without a reversible splenial lesion are similar to 'benign convulsions with mild gastroenteritis'; therefore, continuation of antiseizure medication does not seem necessary.

Increased adolescent game usage and health-related risk behaviors during the COVID-19 pandemic.

This study examines adolescent game usage and corresponding health-related risk behaviors during a period of limited social interaction and activity due to the COVID-19 pandemic. Participants included 225 middle- and 225 high-school students in Seoul who completed a survey online from October 1 to 30, 2021. The study measured participants' game usage level and the health-related risk behavior index. Findings showed that participants who engaged in excessive gaming showed higher levels of health-related risk behaviors. A multivariate analysis of variance was conducted to compare the health-related risk behaviors of students in the general, potential, and high-risk groups on excessive gaming. Results indicated that female students in the high-risk group showed higher stress levels and fatigue (f = 5.549, p < .01, Cohen's d = 0.016) than the males of the same group. However, male students showed higher physical inactivity levels (f = 3.195, p > .05, Cohen's d = 0.009) than females. The post hoc test indicated clear sex distinctions among the general, potential, and high-risk groups on excessive gaming (p < .001). Among the high-risk game usage group, female students displayed a higher level of risk behaviors than males. Adolescent gaming addiction should be considered an emotional and behavioral disorder for which parental guidance and support are needed, and counseling experts and professionals must come together to provide a cure and reform program.

Immunisation with purified Coxiella burnetii phase I lipopolysaccharide confers partial protection in mice independently of co-administered adenovirus vectored vaccines.

Q fever is a highly infectious zoonosis caused by the Gram-negative bacterium Coxiella burnetii. The worldwide distribution of Q fever suggests a need for vaccines that are more efficacious, affordable, and does not induce severe adverse reactions in vaccine recipients with pre-existing immunity against Q fever. Potential Q fever vaccine antigens include lipopolysaccharide (LPS) and several C. burnetii surface proteins. Antibodies elicited by purified C. burnetii lipopolysaccharide (LPS) correlate with protection against Q fever, while antigens encoded by adenoviral vectored vaccines can induce cellular immune responses which aid clearing of intracellular pathogens. In the present study, the immunogenicity and the protection induced by adenoviral vectored constructs formulated with the addition of LPS were assessed. Multiple vaccine constructs encoding single or fusion antigens from C. burnetii were synthesised. The adenoviral vectored vaccine constructs alone elicited strong cellular immunity, but this response was not correlative with protection in mice. However, vaccination with LPS was significantly associated with lower weight loss post-bacterial challenge independent of co-administration with adenoviral vaccine constructs, supporting further vaccine development based on LPS.

COVID-19 Vaccine-Associated Pneumonitis in the Republic of Korea: A Nationwide Multicenter Survey.

BACKGROUND: Recent reports have suggested that pneumonitis is a rare complication following vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, its clinical features and outcomes are not well known. The aim of this study was to identify the clinical characteristics and outcomes of patients with vaccine-associated pneumonitis following vaccination against SARS-CoV-2. METHODS: In this nationwide multicenter survey study, questionnaires were distributed to pulmonary physicians in referral hospitals. They were asked to report cases of development or exacerbation of interstitial lung disease (ILD) associated with the coronavirus disease 2019 vaccine. Vaccine-associated pneumonitis was defined as new pulmonary infiltrates documented on chest computed tomography within 4 weeks of vaccination and exclusion of other possible etiologies. RESULTS: From the survey, 49 cases of vaccine-associated pneumonitis were identified between February 27 and October 30, 2021. After multidisciplinary discussion, 46 cases were analyzed. The median age was 66 years and 28 (61%) were male. The median interval between vaccination and respiratory symptoms was 5 days. There were 20 (43%), 17 (37%), and nine (19%) patients with newly identified pneumonitis, exacerbation of pre-diagnosed ILD, and undetermined pre-existing ILD, respectively. The administered vaccines were BNT162b2 and ChAdOx1 nCov-19/AZD1222 each in 21 patients followed by mRNA-1273 in three, and Ad26.COV2.S in one patient. Except for five patients with mild disease, 41 (89%) patients were treated with corticosteroid. Significant improvement was observed in 26 (57%) patients including four patients who did not receive treatment. However, ILD aggravated in 9 (20%) patients despite treatment. Mortality was observed in eight (17%) patients. CONCLUSION: These results suggest pneumonitis as a potentially significant safety concern for vaccines against SARS-CoV-2. Clinical awareness and patient education are necessary for early recognition and prompt management. Additional research is warranted to identify the epidemiology and characterize the pathophysiology of vaccine-associated pneumonitis.

Secondary Risk in COVID-19 Vaccination Intentions: A Theoretical Contribution to the Protection Motivation Paradigm.

This study presents an original model that features the emotion of fear of COVID-19 as a direct effect on vaccination intentions. A central research question addressed in the study is what roles do the emotion of fear of contracting COVID-19 and the threat posed by uptake of the COVID-19 vaccination play in levels of vaccination intention? The study used a structural equation model (SEM) and applied the SmartPLS 3.2.6 data analysis tool for model estimation and multivariate analysis variables. A key finding is that vaccination resistance is strongest when fear of COVID-19 is lower, and vaccination threat higher. Vaccination threat appraisal and vaccination intention were found to have a negative relationship. Response costs at higher levels lessen motivation for COVID-19 vaccination. Research implications include research-based targeting of differing segments by their primary fear, either fear of COVID-19 or of the preventative vaccine.

SARS-CoV-2 molecular diagnostic point-of-care testing based on loop-mediated isothermal amplification: A prospective, single-center validation study

Objectives Rapid and accurate severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) diagnostic tests are crucial for controlling the spread of infections in emergency settings. This study evaluated the diagnostic accuracy of a point-of-care (POC) test based on loop-mediated isothermal amplification (LAMP) that produces rapid results within 30 min. Methods We prospectively included adult patients (age >19 years) who were diagnosed with SARS-CoV-2 infection within the last 3 days and symptomatic patients who had visited the emergency room. Posterior nasopharyngeal (PNP) swabs and throat swabs collected by physicians were used to test the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), accuracy, and Cohen's Kappa coefficient (k) of the POC index and reference reverse transcription quantitative polymerase chain reaction (RT-qPCR) test devices. Results Of the 352 participants, 102 (29.0%) tested positive via the RT-PCR-based reference test device;the RT-LAMP-based POC test had a sensitivity of 70.6% and specificity of 98.0%, with 93.5% PPV, 89.1% NPV, 35.5% PLR, and 3.4% NLR. Cohen's k correlation of results from the two devices was 0.74. The cycle threshold value between the positive and negative POC test results differed (17.6 vs. 24.6, p < 0.001). Conclusions The RT-LAMP POC test in the emergency medical setting has a fair predictive value in high viral load cases in terms of infectivity.

In vitro metabolic characterization of the SARS-CoV-2 papain-like protease inhibitors GRL0617 and HY-17542

The SARS-CoV-2 pandemic requires a new therapeutic target for viral infection, and papain-like protease (Plpro) has been suggested as a druggable target. This in-vitro study was conducted to examine the drug metabolism of the GRL0617 and HY-17542, Plpro inhibitors. Metabolism of these inhibitors was studied to predict the pharmacokinetics in human liver microsomes. The hepatic cytochrome P450 (CYP) isoforms responsible for their metabolism were identified using recombinant enzymes. The drug–drug interaction potential mediated by cytochrome P450 inhibition was estimated. In human liver microsomes, the Plpro inhibitors had phase I and phase I + II metabolism with half-lives of 26.35 and 29.53 min, respectively. Hydroxylation (M1) and desaturation (-H2, M3) of the para-amino toluene side chain were the predominant reactions mediated with CYP3A4 and CYP3A5. CYP2D6 is responsible for the hydroxylation of the naphthalene side ring. GRL0617 inhibits major drug-metabolizing enzymes, including CYP2C9 and CYP3A4. HY-17542 is structural analog of GRL0617 and it is metabolized to GRL0617 through non-cytochrome P450 reactions in human liver microsomes without NADPH. Like GRL0617 and HY-17542 undergoes additional hepatic metabolism. The in-vitro hepatic metabolism of the Plpro inhibitors featured short half-lives;preclinical metabolism studies are needed to determine therapeutic doses for these inhibitors.

Multi-omics of NET formation and correlations with CNDP1, PSPB, and L-cystine levels in severe and mild COVID-19 infections

The detailed mechanisms of COVID-19 infection pathology remain poorly understood. To improve our understanding of SARS-CoV-2 pathology, we performed a multi-omics and correlative analysis of an immunologically naïve SARS-CoV-2 clinical cohort from blood plasma of uninfected controls, mild, and severe infections. Consistent with previous observations, severe patient populations showed an elevation of pulmonary surfactant levels. Intriguingly, mild patients showed a statistically significant elevation in the carnosine dipeptidase modifying enzyme (CNDP1). Mild and severe patient populations showed a strong elevation in the metabolite L-cystine (oxidized form of the amino acid cysteine) and enzymes with roles in glutathione metabolism. Neutrophil extracellular traps (NETs) were observed in both mild and severe populations, and NET formation was higher in severe vs. mild samples. Our correlative analysis suggests a potential protective role for CNDP1 in suppressing PSPB release from the pulmonary space whereas NET formation correlates with increased PSPB levels and disease severity. In our discussion we put forward a possible model where NET formation drives pulmonary occlusions and CNDP1 promotes antioxidation, pleiotropic immune responses, and vasodilation by accelerating histamine synthesis.

COVID-19 Outbreak in a Military Unit in Korea.

OBJECTIVES: This study presents the response of a military unit to the COVID-19 outbreak in Gyeonggi Province. As soon as two soldiers were identified as index cases, the infectious disease investigators of the Gyeonggi Provincial Government, Korea Disease Control and Prevention Agency and the Armed Forces Epidemiologic Investigation Center, discussed the investigation and response plan for an imminent massive outbreak. METHODS: The joint immediate response team (IRT) conducted interviews with confirmed patients with COVID-19, reviewed medical records, performed contact tracing using global positioning system (GPS), and undertook a field investigation. For risk assessment, the joint IRT visited all eight sites of the military units and the army chaplain's church to evaluate the transmission risk of each site. The evaluation items included the size of the site, the use of air conditioning, whether windows were opened, and whether masks were worn. A pooled testing was used for a low-risk population to quickly detect the spread of COVID-19 in the military base. RESULTS: A day before the symptom onset of the index case, the lecturer and >50% of the attendees were infected with COVID-19 while attending a lecture that lasted 2 h and 30 min. Attendees were not wearing masks and were in a poorly ventilated room. CONCLUSION: Since the disease can be spread before symptom onset, contact tracing must be performed to investigate potential exposures prior to symptom onset and manage any exposed persons.

Deep Learning With Chest Radiographs for Making Prognoses in Patients With COVID-19: Retrospective Cohort Study.

BACKGROUND: An artificial intelligence (AI) model using chest radiography (CXR) may provide good performance in making prognoses for COVID-19. OBJECTIVE: We aimed to develop and validate a prediction model using CXR based on an AI model and clinical variables to predict clinical outcomes in patients with COVID-19. METHODS: This retrospective longitudinal study included patients hospitalized for COVID-19 at multiple COVID-19 medical centers between February 2020 and October 2020. Patients at Boramae Medical Center were randomly classified into training, validation, and internal testing sets (at a ratio of 8:1:1, respectively). An AI model using initial CXR images as input, a logistic regression model using clinical information, and a combined model using the output of the AI model (as CXR score) and clinical information were developed and trained to predict hospital length of stay (LOS) ≤2 weeks, need for oxygen supplementation, and acute respiratory distress syndrome (ARDS). The models were externally validated in the Korean Imaging Cohort of COVID-19 data set for discrimination and calibration. RESULTS: The AI model using CXR and the logistic regression model using clinical variables were suboptimal to predict hospital LOS ≤2 weeks or the need for oxygen supplementation but performed acceptably in the prediction of ARDS (AI model area under the curve [AUC] 0.782, 95% CI 0.720-0.845; logistic regression model AUC 0.878, 95% CI 0.838-0.919). The combined model performed better in predicting the need for oxygen supplementation (AUC 0.704, 95% CI 0.646-0.762) and ARDS (AUC 0.890, 95% CI 0.853-0.928) compared to the CXR score alone. Both the AI and combined models showed good calibration for predicting ARDS (P=.079 and P=.859). CONCLUSIONS: The combined prediction model, comprising the CXR score and clinical information, was externally validated as having acceptable performance in predicting severe illness and excellent performance in predicting ARDS in patients with COVID-19.

Impact of COVID-19 on Out-of-Hospital Cardiac Arrest in Korea.

BACKGROUND: Coronavirus disease 2019 (COVID-19) is a global public health crisis that has had a significant impact on emergency medical services (EMS). Several studies have reported an increase in the incidence of out-of-hospital cardiac arrest (OHCA) and a decreased survival due to COVID-19, which has been limited to a short period or has been reported in some regions. This study aimed to investigate the effect of COVID-19 on OHCA patients using a nationwide database. METHODS: We included adult OHCA patients treated by EMS providers from January 19, 2019 to January 20, 2021. The years before and after the first confirmed case in Korea were set as the non-COVID-19 and COVID-19 periods, respectively. The main exposure of interest was the COVID-19 period, and the primary outcome was prehospital return of spontaneous circulation (ROSC). Other OHCA variables were compared before and after the COVID-19 pandemic and analyzed. We performed a multivariable logistic regression analysis to understand the independent effect of the COVID-19 period on prehospital ROSC. RESULTS: The final analysis included 51,921 eligible patients, including 25,355 (48.8%) during the non-COVID-19 period and 26,566 (51.2%) during the COVID-19 period. Prehospital ROSC deteriorated during the COVID-19 period (10.2% vs. 11.1%, P = 0.001). In the main analysis, the adjusted odds ratios (AORs) for prehospital ROSC showed no significant differences between the COVID-19 and non-COVID-19 periods (AOR [95% confidence interval], 1.02 [0.96-1.09]). CONCLUSION: This study found that the proportion of prehospital ROSC was lower during the COVID-19 period than during the non-COVID-19 period; however, there was no statistical significance when adjusting for potential confounders. Continuous efforts are needed to restore the broken chain of survival in the prehospital phase and increase the survival rate of OHCA patients.

Pregnancy and COVID-19: past, present and future.

Current evidence suggests that severe acute respiratory syndrome coronavirus 2 infection is associated with an increased incidence of adverse severe maternal and perinatal outcomes. However, vertical transmission is rare. The management of pregnant women with coronavirus disease 2019 (COVID-19) is similar to that of non-pregnant women, and effective treatments, including antiviral therapy, dexamethasone, and prophylactic anticoagulation should not be withheld during pregnancy. During the early COVID-19 pandemic period, the management of pregnant women was often delayed until the polymerase chain reaction (PCR) results came out or due to close contact, even among those without symptoms. Out of concern for the spread of infection, cesarean sections were performed instead of vaginal birth, since infection could have led to an increase in maternal and neonatal morbidities. Additionally, if the maternal PCR test was positive, the neonate was quarantined, and despite infectivity decreasing 10 days after symptom onset. It is necessary to ease the strict measures of infection control in the field of obstetrics. The presence or absence of maternal COVID-19 symptoms should be identified to stratify the risk, and vaginal delivery can be attempted in asymptomatic women with low infectivity. With more women being vaccinated safety data about vaccination is rapidly accumulating and no concerns have been detected. Globally, COVID-19 vaccines are recommended even during pregnancy. In order to prepare for future pandemics, it is necessary to apply lessons learned from this pandemic. Policymakers and healthcare leaders must determine efficient and effective strategies for preserving safe maternal care, even during an ongoing global emergency.

Variation in leisure sport conflicts and coping strategies depending on participation type and proximity during the COVID-19 pandemic.

Introduction: New conflict types have arisen in leisure sports activities due to social regulations designed to address COVID-19. We analyze the differences in conflict-inducing factors and coping strategies across various types of leisure sports and levels of spatial proximity. Methods: Korean adults aged between 20 and 60 years, who had participated in leisure sports activities since the COVID-19 outbreak in January 2020, were surveyed, and 508 responses were collected for analysis. The differences in leisure sports conflicts and coping strategies across the types of leisure sports participation and spatial proximity were tested. Results: The results show that conflict due to prejudice was higher in typical indoor sports activities, such as Pilates, yoga, and gym workouts, whereas conflict due to competition or not observing etiquette was higher in indoor golf. Second, conflict due to prior expectations and prejudice was high in outdoor sports activities, such as jogging and hiking. Finally, all participants showed avoidance behavior, but it was observed more frequently in outdoor sports than indoor sports. Discussion: The study reveals how much leisure conflict is induced by various types of leisure sports participation, particularly during outdoor activities, which usually feature a relatively low density of participants. It underscores the necessity of developing structural approaches to resolving leisure conflicts in dangerous spaces or requiring intensive management and creating new leisure sports activities.

A study on blood donor characteristics and preferred environment of South Koreans during the COVID-19 pandemic: A conjoint analysis.

Objective: The COVID-19 pandemic has caused a decrease in the number of blood donors worldwide, posing a global problem. Therefore, this study investigates people who have continuously participated in blood donation during the COVID-19 pandemic and collects basic information as a reference for maintaining stable amounts of blood during future pandemics. Methods: The participants of this study were selected from the population of South Korea through stratified sampling considering region and age distributions. Owing to the COVID-19 pandemic, the participants were recruited online through Embrain, an online research and survey company, from June 1 to June 28, 2021. Data were collected from a total of 1,043 participants and used in the study. Results: The results of this study showed that there was a difference between the donors group and non-donors group in factors such as donation attitude (F = 73.342, p < 0.001), donation knowledge (F = 6.530, p < 0.01), and preventive health behavior (F = 12.352, p < 0.001). Overall, blood donors showed favorable attitude toward and considerable knowledge of blood donation as well as a high level of preventive health behavior. The environment most preferred by people who participated in blood donation during the COVID-19 pandemic was "going with family to a blood donation center that gives out free gifts in a region far away with no confirmed cases," which showed the highest utility (utility = 0.734). Conclusion: Even during pandemics, donation attitude, donation knowledge, and preventive health behavior can serve as key factors affecting participation in blood donation. Additionally, blood donation centers that donors can visit with their families represent a favorable environment for the promotion of blood donation during pandemics.

Impact of COVID-19 infection on sports performance of elite university athletes.

BACKGROUND: Cardiopulmonary functions of athletes can be affected by the Coronavirus disease 2019 (COVID-19). This study aimed to investigate athletes' pattern of returning to sports after COVID-19, their experience of COVID-19-associated symptoms, and the disturbance in sports performance caused by the symptoms. METHODS: Elite university athletes who were infected with COVID-19 in 2022 were recruited for the survey and the data for 226 respondents were analyzed. Information about COVID-19 infection and the degree of disturbance in ordinary training and competition was collected. Their returning pattern to sports, the prevalence of COVID-19 symptoms, the degree of disturbance in sports by related symptoms, and factors associated with disturbance in sports and fatigue were analyzed. RESULTS: Results showed that 53.5% of the analyzed athletes returned to ordinary training immediately after quarantine, while 61.5% experienced disturbance in ordinary training, and 30.9% experienced that in competition. Most prevalent COVID-19 symptoms were lack of energy, easy fatiguability and cough. Disturbance in ordinary training and competition were mainly related to generalized, cardiologic, and respiratory symptoms. Women and those with severe and generalized symptoms had significantly higher odds of experiencing disturbance in training. Those with cognitive symptoms had higher odds of being "fatigue case." CONCLUSIONS: More than half of the athletes returned immediately to sports after the legal quarantine period of COVID-19 infection and experienced disturbance in ordinary training by related symptoms. Prevalent COVID-19 symptoms and the associated factors causing disturbance in sports and fatigue case were also revealed. This study will be helpful to establish the safe return guidelines essential for athletes after COVID-19.